It no longer hinges on Kelecgos or the tier 5 one that increases stats based on how many dragons you have. They are still good, but don't define the build anymore.
The new Dragons just thoroughly outclass Razorgore, and you need like 4 Battlecries a turn for Kalecgos to be as good as a Proto/Talec so you it's not as good as the new Dragons either. If it weren't for Nadina, my advice for Ysera players would be to never, ever go to Tier 5. (But you still totally want Nadina.)
I would still say that as Ysera you shouldn't go Tier 5 until you get a Triple. And generally you want to avoid Tier 5 and go straight from 4 to 6, after hanging around on 4 for a good long time.
The new Dragons just thoroughly outclass Razorgore, and you need like 4 Battlecries a turn for Kalecgos to be as good as a Proto/Talec so you it's not as good as the new Dragons either. If it weren't for Nadina, my advice for Ysera players would be to never, ever go to Tier 5. (But you still totally want Nadina.)
I would still say that as Ysera you shouldn't go Tier 5 until you get a Triple. And generally you want to avoid Tier 5 and go straight from 4 to 6, after hanging around on 4 for a good long time.